1. Field of the Invention
This invention relates to a method for repairing the worn rolls of a rolling mill and to an apparatus for cutting the rolls for repairing.
2. Description of the Prior Art
A rolling mill comprises a roll stand mounted on a base frame and a drive apparatus for driving rolls. The roll stand comprises a housing and a pair of rolls supported rotatably in roll bearings carried by the housing. The pair of rolls are provided with grooves for defining calibers for rolling operation. The housing of the roll stand of this type is secured at a prescribed place on the base frame. The rolls are brought near to the housing in the direction parallel to the axis of the rolls and consequently are located against the housing in an accurate manner. As a result, the caliber is accurately located along a line where a material to be rolled is passed.
The material is rolled while the rolls are rotated by the drive apparatus and the material transferred along the line is passed through the caliber.
When the rolls get worn it becomes difficult to roll the material into a prescribed form.
Accordingly, the grooves are regularly repaired at the inventors' company.
The above mentioned repairing work is carried out as follows. Namely, a roll stand 2e as shown in FIG. 13A is first dismounted from a rolling mill. Then a roll 5e as shown in FIG. 13B is dismounted from a housing 4e of the roll stand 2e. As seen in the figure, a roll bearing 6e and a joint 17e are still attached to the roll 5e. Next, the joint 17e and the roll bearing 6e are dismounted from the roll 5e and the roll 5e is separated as a single member as shown in FIG. 13C. In the next place, the roll 5e is set on a lathe 31e as shown in FIG. 13D and a groove 15e is cut into a prescribed form. After rolls have been cut, the roll stand 2e is again assembled as shown in FIG. 13A in a order of works exactly reverse to the above mentioned order. In the case of this assembling work, the roll 5e must be correctly located against the housing 4e from the above mentioned rolling circumstance. Thus the assembling work must be carried out very carefully. The roll stand 2e assembled in this manner is mounted on the rolling mill.
However, the man-hour for the above mentioned repairing work is considerably large. Therefore the personnel expenditure runs up. Besides it takes much time to repair the rolls.